Class AbstractJsonWriter

    • Field Detail

      • DROP_ROOT_MODE

        public static final int DROP_ROOT_MODE
        DROP_ROOT_MODE drops the JSON root node.

        The root node is the first level of the JSON object i.e.

         { "person": {
             "name": "Joe"
         }}
         

        will be written without root simply as

         {
             "name": "Joe"
         }
         

        Without a root node, the top level element might now also be an array. However, it is possible to generate invalid JSON unless STRICT_MODE is also set.

        Since:
        1.3.1
        See Also:
        Constant Field Values
      • STRICT_MODE

        public static final int STRICT_MODE
        STRICT_MODE prevents invalid JSON for single value objects when dropping the root.

        The mode is only useful in combination with the DROP_ROOT_MODE. An object with a single value as first node i.e.

         { "name": "Joe" }
         

        is simply written as

         "Joe"
         

        However, this is no longer valid JSON. Therefore you can activate STRICT_MODE and a ConversionException is thrown instead.

        Since:
        1.3.1
        See Also:
        Constant Field Values
      • EXPLICIT_MODE

        public static final int EXPLICIT_MODE
        EXPLICIT_MODE assures that all data has its explicit equivalent in the resulting JSON.

        XStream is normally using attributes in XML that have no real equivalent in JSON. Additionally it is essential in XML that the individual child elements of a tag keep order and may have the same tag name. XStream's model relies on both characteristics. However, properties of a JSON object do not have a defined order, but their names have to be unique. Only a JSON array defines the order of its elements.

        Therefore XStream uses in explicit mode a JSON format that supports the original requirements at the expense of the simplicity of the JSON objects and arrays. Each Java object will be represented by a JSON object with a single property representing the name of the object and an array as value that contains two more arrays. The first one contains a JSON object with all attributes, the second one the value of the Java object which can be null, a string or integer value or again a new JSON object representing a Java object. Here an example of an string array with one member, where the array and the string has an additional attribute 'id':

         {"string-array":[[{"id":"1"}],[{"string":[[{"id":"2"}],["Joe"]]}]]}
         

        This format can be used to always deserialize into Java again.

        This mode cannot combined with STRICT_MODE or DROP_ROOT_MODE.

        Since:
        1.4
        See Also:
        Constant Field Values
      • IEEE_754_MODE

        public static final int IEEE_754_MODE
        IEEE_754_MODE keeps precision of 64-bit integer values.

        In JavaScript every number is expressed as 64-bit double value with a precision of 53 bits following IEEE 754. Therefore it is not possible to represent the complete value range of 64-bit integer values. Any integer value > 253 (9007199254740992) or < -253 (-9007199254740992) will therefore be written as string value.

        CAUTION: A client must be aware that the element may contain a number or a string value.

        Since:
        1.4.5
        See Also:
        ECMA Specification: The Number Type, Constant Field Values
      • STATE_START_ATTRIBUTES

        private static final int STATE_START_ATTRIBUTES
        See Also:
        Constant Field Values
      • NUMBER_TYPES

        private static final java.util.Set NUMBER_TYPES
      • mode

        private int mode
      • expectedStates

        private int expectedStates
    • Constructor Detail

      • AbstractJsonWriter

        public AbstractJsonWriter()
        Construct a JSON writer.
        Since:
        1.4
      • AbstractJsonWriter

        public AbstractJsonWriter​(int mode)
        Construct a JSON writer with a special mode.
        Parameters:
        mode - a bit mask of the mode constants
        Since:
        1.4
      • AbstractJsonWriter

        public AbstractJsonWriter​(NameCoder nameCoder)
        Construct a JSON writer with a special name coder.
        Parameters:
        nameCoder - the name coder to use
        Since:
        1.4
      • AbstractJsonWriter

        public AbstractJsonWriter​(int mode,
                                  NameCoder nameCoder)
        Construct a JSON writer with a special mode and name coder.
        Parameters:
        mode - a bit mask of the mode constants
        nameCoder - the name coder to use
        Since:
        1.4
    • Method Detail

      • startNode

        public void startNode​(java.lang.String name)
      • addAttribute

        public void addAttribute​(java.lang.String name,
                                 java.lang.String value)
      • setValue

        public void setValue​(java.lang.String text)
        Description copied from interface: HierarchicalStreamWriter
        Write the value (text content) of the current node.
      • endNode

        public void endNode()
      • handleCheckedStateTransition

        private void handleCheckedStateTransition​(int requiredState,
                                                  java.lang.String elementToAdd,
                                                  java.lang.String valueToAdd)
      • handleStateTransition

        private int handleStateTransition​(int currentState,
                                          int requiredState,
                                          java.lang.String elementToAdd,
                                          java.lang.String valueToAdd)
      • getType

        protected AbstractJsonWriter.Type getType​(java.lang.Class clazz)
        Method to return the appropriate JSON type for a Java type.
        Parameters:
        clazz - the type
        Returns:
        One of the AbstractJsonWriter.Type instances
        Since:
        1.4.4
      • isArray

        protected boolean isArray​(java.lang.Class clazz)
        Method to declare various Java types to be handles as JSON array.
        Parameters:
        clazz - the type
        Returns:
        true if handles as array
        Since:
        1.4
      • startObject

        protected abstract void startObject()
        Start a JSON object.
        Since:
        1.4
      • addLabel

        protected abstract void addLabel​(java.lang.String name)
        Add a label to a JSON object.
        Parameters:
        name - the label's name
        Since:
        1.4
      • addValue

        protected abstract void addValue​(java.lang.String value,
                                         AbstractJsonWriter.Type type)
        Add a value to a JSON object's label or to an array.
        Parameters:
        value - the value itself
        type - the JSON type
        Since:
        1.4
      • startArray

        protected abstract void startArray()
        Start a JSON array.
        Since:
        1.4
      • nextElement

        protected abstract void nextElement()
        Prepare a JSON object or array for another element.
        Since:
        1.4
      • endArray

        protected abstract void endArray()
        End the JSON array.
        Since:
        1.4
      • endObject

        protected abstract void endObject()
        End the JSON object.
        Since:
        1.4